Eggshell was found to be a versatile heterogeneous catalyst for the synthesis of pyrano[3,2-c]quinoline derivatives in good yields. This protocol has the advantages of environmental friendliness, short reaction time, low cost and convenient operation.

Article history: Received 6 August 2008 Accepted 18 February 2009 Available online 27 February 2009

The asymptotic many-server queue with abandonments, G/GI/N +GI , is considered in the qualityand efficiency-driven (QED) regime. Here the number of servers and the offered load are related via the square-root rule, as the number of servers increases indefinitely. QED performance entails short waiting times and scarce abandonments (high quality) jointly with high servers’ utilization (high effic...

The present investigation deals with the bulk arrival M/G/1 retrial queue with impatient customers and modified vacation policy. The incoming customers join the virtual pool of customers called orbit if they find the server being busy, on vacation or in broken down state otherwise the service of the customer at the head of the batch is started by the server. The service is provided in k</em...

Effective knowledge and awareness of customers require the market segmentation, through which the customers who have the same needs and purchasing patterns as well as the same response to marketing plans are identified. The selection of a proper variable is a requirement, among other, for a successful market segmentation. In today' world, on one hand, the consumers are bombarded with new goods ...

Across an array of contexts, a ‘female-friendly environment’ is increasingly thought to positively impact participation levels for women and girls. The aim this study provide insights on the female-friendliness New Zealand’s tennis clubs. Both numeric text data were collected as part 2021 National Sport Club Survey. Tennis club representatives agreed more strongly that their has suitable changi...

Electrification of transportation is critical for a lowcarbon society. In particular, public vehicles (e.g., taxis) provide a crucial opportunity for electrification. Despite the benefits of eco-friendliness and energy efficiency, adoption of electric taxis faces several obstacles, including constrained driving range, long recharging duration, limited charging stations and low gas price, all of...

We consider an infinite-horizon single-product pricing problem in which a fraction of customers is patient and the remaining fraction is impatient. A patient customer will wait up to some fixed number of time periods for the price of the product to fall below his or her valuation at which point the customer will make a purchase. If the price does not fall below a patient customer's valuation at...

In this paper, we examine the problem of choosing discriminatory prices for customers with probabilistic valuations and a seller with indistinguishable copies of a good. We show that under certain assumptions this problem can be reduced to the continuous knapsack problem (CKP). We present a new fast ǫ-optimal algorithm for solving CKP instances with asymmetric concave reward functions. We also ...